The purposes of this study have been to determine the value of staging laparotomy on evaluating the accuracy of the extent of abdominal disease at the time of initial evaluation and what influence this has on the initial therapy for patients with early stage Hodgkin's disease. 175 patients with Hodgkin's disease have undergone staging laparotomy and splenectomy, and this has revealed that the pre-operative assessment of the extended abdominal involvement was incorrect in approximately 40 percent of these cases. The prediction of splenic involvement by Hodgkin's disease was incorrect in one-third of the patients and approximately one-third of abnormal lymphangiograms could not be confirmed at laparotomy and a number of cases of involvement of nodes in the porta hepatic region outside the usual radiation therapy ports were dicovered. A small number a patients were also found to have documented liver involvement which had not been suspected by preoperative evaluation. These findings have altered the therapeutic approaches significantly in the number of patients. It has also been determined that patients presenting with supradiaphragmatic Hodgkin's disease have occult disease limited to the spleen, splenic hilum and celiac axis in most cases in which abdominal tumor was documented at laparotomy. The results of these studies have been important in the subsequent design of our further therapeutic protocols for the treatment of stages IA to IIIA Hodgkin's disease.